A stunning amount of information is being demanded from the Chicago Police Department from the special prosecutor in the Laquan McDonald case, records obtained by NBC 5 Investigates show. (Published Friday, Jan. 13, 2017)

A stunning amount of information is being demanded from the Chicago Police Department from the special prosecutor in the Laquan McDonald case, records obtained by NBC 5 Investigates show.

The demands come ahead of the Department of Justice’s announcement on its 13-month investigation into the police department expected Friday morning.

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(Published Friday, Jan. 13, 2017)

Dashcam video of the 17-year-old's shooting was released in 2015, prompting nationwide protests. Officer Jason Van Dyke, who shot McDonald 16 times as he appeared to walk away from police, has been charged with first-degree murder.

A subpoena orders police to produce any messages sent by officers who were on the scene of the fatal shooting and investigation. The list includes social media platforms including Group Me, WeChat, WhatsApp, Facebook, LinkedIn, Twitter, YouTube and Snapchat.

“When you have a number of officers all saying the same thing and that thing isn't true ... the likely explanation is that they got together or used text messaging to get their story straight before they talked to investigators,” said Mat Topic, an attorney with the civil rights firm Loevy and Loevy.

What happened in dashcam video of the shooting contradicted many of the accounts given by Chicago police officers to investigators. The subpoena says a special grand jury was scheduled to convene on Tuesday to look into a possible cover-up.

“Our officers are being asked to do a very difficult job in very trying areas,” Mayor Rahm Emanuel said Thursday. “Change is very hard—we’re making changes—and the biggest thing we can do to help our officers is support them.”

The subpoena obtained by NBC 5 also expanded the amount of CPD dashcam videos from 5 to 13 vehicles.